The first step to solving this expression is to remove the first set of parenthesis and then remove the parenthesis from all positive numbers.
-9 - 9 × (-3) - 8 × (-7)
Multiply the numbers -9 and (-3) together.
-9 + 27 - 8 × (-7)
Multiply the numbers -8 and (-7) together.
-9 + 27 + 56
Lastly,, use addition and subtraction rules to calculate the expression and find your final answer.
74.
This means that the final answer to your expression is 74.
Let me know if you have any further questions
:)